Let there be LED: The future of the light bulb

This article was taken from the October 2011 issue of Wired
magazine. Be the first to read Wired's articles in print before
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Brett Sharenow is presiding over the Pepsi Challenge of
lightbulbs. The CFO of Switch, a Silicon Valley
startup, Sharenow has set himself up in a small booth at the
back of the Pennsylvania Convention Center in Philadelphia, and
he's asking passers-by to check out two identical white shades.
Behind one hides a standard incandescent bulb, the familiar
lighting technology that has gone largely unchanged since Thomas
Edison invented it 132 years ago. Behind the other is a stunning,
almost Art Deco-style prototype that holds ten LEDs and a secret fluid. It's a liquid-cooled bulb, as
radically different from Edison's invention as anything that's ever
been screwed into a standard socket and, Sharenow hopes, the next
big thing in the £18 billion lighting industry. The challenge: can
you tell which is which?

It's day one of Lightfair, the annual international trade show
for everything that glows, glares, flickers or shines -- 500
exhibitors and 24,000 visitors prowling row after row of light
after light. This is the last Lightfair before new regulations
governing light-bulb efficiency begin to take effect in the US in
January, and there's a real sense of history and urgency on the
show floor. Ready or not, the way that Americans -- and EU citizens
-- light homes and offices is about to change, and the technology
that will lead the way is somewhere in this hall. In the US, the
provisions of 2007's Energy Independence and Security Act will
effectively ban all incandescent bulbs by 2014. In the European
Union, all incandescents will be banned for use in the home by
2012. They will mostly be replaced throughout the 27-state bloc
with "compact fluorescent light" (CFL) bulbs, which have attracted
much criticism, not least for their mercury content. So the race to
find a better replacement for fluorescents is still very much
alive. The industry is banking on LED lighting, and it's virtually
the only bulb technology on display at Lightfair: there's barely a
single incandescent or sickly CFL to be seen. Just 6,000m2 of
companies racing to fill the world's billions of standard sockets
-- and betting on LEDs as the way to do it.

There's an excellent reason why LEDs have taken on the aura of
inevitability: they are semiconductors, and like all solid-state
technology they are getting better and cheaper on a predictable
curve. In 1999, a researcher named Roland Haitz, then head of
semiconductor R&D at Hewlett-Packard,
coauthoured a paper that became known as "Haitz's Law", the
lighting industry's manifesto. By charting the historical prices of
LEDs and projecting forward, Haitz estimated that the amount of
light that they produced would increase by a factor of 20 per
decade, while the cost would drop by a factor of ten. Haitz's Law
has proven remarkably accurate. But the lighting industry still has
major hurdles to clear before LEDs gain acceptance from consumers.
Beyond the very real technical issues -- cooling, costs, light
colour -- there's the public's lingering distaste for CFLs, which
in the US failed miserably in their projected role as the bulb of
the future. That sentiment has fed into a Tea Party-fuelled backlash against the regulations -- with
attempts to roll them back entirely.

Incandescents convert less than ten percent of the energy pumped
into them into light, losing the rest as heat. More efficient bulbs
could save billions of pounds, decrease dependence on foreign oil, and
significantly reduce greenhouse gases. Still, the consumer backlash
resonates and not simply because CFLs are horrible, flickery, ugly
and unreliable. Evolutionary
biologists believe that human lighting preferences are the
result of our trichromatic vision (possessing three independent
channels for conveying colour information) -- rare in non-primates
-- which makes us particularly suited to daylight and the
perception of primary colours. There's an anthropological component
as well: for 400,000 years, humankind has been banishing darkness
with fire. And Edison's bulb is, at its core, a burning filament.
Abandoning incandescents means abandoning fire as a light source
for the first time in our history.

The front of the hall at Lightfair is the province of the
industry's big three -- Philips, Osram Sylvania and General
Electric (GE), founded by Edison. The behemoths give way to a
second tier occupied by the likes of Toshiba, Samsung, Leviton and
Honeywell. Behind them, smaller companies -- accessory makers,
vendors and Asian component suppliers -- fill out the rest of the
available floor space, right up to the back wall. Here, Sharenow is
presiding over the Switch booth.

"Which one is which?" Sharenow asks. Most people get it wrong,
which is significant. When they select what they feel is the
superior light, they're selecting the Switch. Though there are
countless 60W LED prototypes in evidence, few are available for
side-by-side comparisons with incandescents. Most are sealed inside
display cases. The Switch bulbs are out in the open: crystalline
shells of clear, faceted glass, with aluminium prongs holding
yellow-tinted LEDs that shine through the cooling liquid to cast a
warm, living-room-quality glow -- and draw only 13 watts to do
it.

Most lightbulbs are rated at or equivalent to 60W or 100W, but
nearly every LED brought to market so far has come in the 40W
equivalency range, good for little beyond cupboards. Brighter bulbs
are either too hot, too expensive (upwards of £30, though they can
last for 20 years) or both. Switch plans to start selling its
60W-equivalent bulb this autumn for around £18. "People have always
needed light," Sharenow says. "This is a light source people will
want."